• Journal of Microbiology and Biotechnology
• /
• v.32 no.3
• /
• pp.333-340
• /
• 2022

Leuconostoc has been used as a principal starter in natural kimchi fermentation, but limited research has been conducted on its phages. In this study, prophage distribution and characterization in kimchi-derived Leuconostoc strains were investigated, and phage induction was performed. Except for one strain, 16 Leuconostoc strains had at least one prophage region with questionable and incomplete regions, which comprised 0.5-6.0% of the bacterial genome. Based on major capsid protein analysis, ten intact prophages and an induced incomplete prophage of Leu. lactis CBA3626 belonged to the Siphoviridae family and were similar to Lc-Nu-like, sha1-like, phiMH1-like, and TPA_asm groups. Bacterial immunology genes, such as superinfection exclusion proteins and methylase, were found on several prophages. One prophage of Leu. lactis CBA3626 was induced using mitomycin C and was confirmed as belonging to the Siphoviridae family. Homology of the induced prophage with 21 reported prophages was not high (< 4%), and 47% identity was confirmed only with TPA_asm from Siphoviridae sp. isolate ct3pk4. Therefore, it is suggested that Leuconostoc from kimchi had diverse prophages with less than 6% genome proportion and some immunological genes. Interestingly, the induced prophage was very different from the reported prophages of other Leuconostoc species.

• The Journal of the Korean Society for Microbiology
• /
• v.20 no.1
• /
• pp.1-11
• /
• 1985

A total of 211 strains of Staphylococcus aureus which included 118 strains isolated from various clinical specimens of admitted patients of University Hospital with systemic or severe cases of infection and 93 strains from infected skin diseases of out-patients of dermatology clinic located in rural area, were tested for the antimicrobial susceptibility to the 12 drugs of common use and the phage typing. An these were subjected to the study of plasmid profile analysis for the molecular epidemiology of nosocomial infections. University Hospital(UH) isolates showed higher frequency of resistance than local clinic(LC) isolates against 10 drugs excluding tetracycline(Tc), and trimethoprim(Tp). The MIC of UH isolates were above than $128{\mu}g/ml$ against 9 drugs except Tc, gentamicin(Gm), and Tp, but LC isolates did not show such a high level of MIC. There was difference of MIC needed to inhibit 90% of strains(MIC90) against each drugs tested between two groups of UH and LC isolates. UH isolates showed 2 to 4 times higher value of MIC90 by two-fold serial dilution of drug concentration than LC isolates. Tp was considered as an effective drug in treatment of staphylococcal infections whereas ampicillin and Gm were appeared to be ineffective. Seventy-three strains(61.9%) of UH isolates and 70(69.9%) of LC were typable with phages from Colindale Reference Laboratory. The prevailing phage type of UH isolates belonged to lytic group II were 27 strains(22.9%) and those of LC isolates belonged to lytic group II were 23 strains(24.7%). Thirteen strains(11.0%) of UH isolates were multiply resistant to more than 5 drugs to 10 drugs but none of LC isolates. Through the lysis method of Kado and Liu followed by agarose gel electrophoresis, none of 211 strains showed plasmid profile. These results were confirmed by re-examination through the method of Birnboim and Doly.

• Food Science of Animal Resources
• /
• v.38 no.1
• /
• pp.88-98
• /
• 2018

In this study, we isolated and characterized a bacteriocin-producing strain and two bacteriophages (P4, A3), showing antimicrobial effects against Clostridium perfringens, from chicken and swine feces by the spot-on-the lawn antagonism method. The selected strain was identified as Streptococcus hyointestinalis by 16S rRNA gene sequencing. The bacteriocin from the isolated strain exhibited strong inhibitory activity against four strains of C. perfringens and all the tested strains of Listeria monocytogenes, and the bacteriocin were highly heat- and pH-stable even at pH 2, pH 10 and $121^{\circ}C$ for 15 min. We also evaluated the combined effects of the isolated bacteriocin and phages. Combining the phage treatments and bacteriocin resulted in a synergetic effect compared with the phage or the bacteriocin alone. In addition, during the probiotic test, the bacteriocin-producing S. hyointestinalis B19 strain reduced the population of C. perfringens significantly. Treatment with S. hyointestinalis B19 and a cocktail of lytic bacteriophages eradicated the C. perfringens KCTC $3269^T$, completely. Consequently, the isolated bacteriocin and bacteriophages represent candidates for effective biocontrol of C. perfringens, and bacteriocin-producing S. hyointestinalis B19 is a potential probiotic candidate for use in domestic animals.

• Korean Journal of Veterinary Research
• /
• v.40 no.3
• /
• pp.515-524
• /
• 2000

The present study was conducted to investigate the phage types(PT) of Salmonella enteritidis(SE) isolated from animals and human patients in Korea during the period 1993-1999. SE were isolated from chickens including the layer and broiler, duck, rat, swine and human patients in nationwide scale. A total of 231 non-human and 14 human SE strains were phage typed and 80.4%(197/245) of SE isolates tested could discriminate as a ten SEPTs including the RDNC by the 10 standard phages, which were brought from the Central Public Health Laboratory in England. In analysing of phage types both animal and human SE isolates, SEPT 4(55.4%) was the most prevalent in domestic animals including the layer(39.3%) and broiler(64.5%), duck(55.5%), and swine(75.0%) since 1993. About 57% of the S enteritidis from human was SEPT 4. Along with SEPT 4, SEPT 1, SEPT 6a, SEPT 7 and SEPT 7a var, SEPT 9b, SEPT 15, SEPT 21b and SEPT 22 were also found from animal and human SE isolates. SEPT 4(40.0%) was isolated from frozen chicken meats imported from China along with SEPT 7 and 7a var strains in this study. In conclusion, SEPT 4 was the most predominant SEPT in our country regardless of animal or human hosts including the Che-Ju island and almost exclusively found in domestic poultry(layer and broiler). During the review period, SEPT 4 has already been spreading continually among the animal hosts since 1993.

• Korean Journal of Microbiology
• /
• v.32 no.3
• /
• pp.198-201
• /
• 1994

The nucleotide sequence of the cohesive end site (cos) of Lactobacillus casei phage J1 genome was determined. Comparison between the nucleotide sequences of the circular cos and the left end of the linear J1 DNA showed that the nicking sites of the terminase were as follows: 5'- GGTCGGCC$\downarrow$ -3' 3'- $\uparrow$CCAGCCGG -5' The cohesive single-stranded ends of J1 were found to be 3'-protruding and composed of 8 nucleotides. The mol% G + C of the cohesive ends was 87.5. The cos site shows dyad symmetry from -33 to + 25 bp if the 5' terminal nucleotide of the left end of the linear J1 DNA is numbered +1. No homology was found among the cos sites of phages reported so far.

• Korean Journal of Microbiology
• /
• v.20 no.4
• /
• pp.210-222
• /
• 1982

Coliphages isolated from Han-River from September 1980 to August 1981 were classified by morphological and physiological characteristics. Effects of soil metrial on the fate of coliphage in nature were investigated. 1. The correlation coefficient between coliphage and E.coli which was host of coliphages in nature was 0.7173 (p=0.004). 2. Coliphage I isolated from Han-River of which DNA molecular weight was $27{\times}10^6$ daltons was identified as $T_1$ phage and coliphage II of which DNA molecular weight $72{\times}10^6$ daltons was classified as $T_5$ phage. 3. Soil material SW was composed of 63.65% silt and 21.92% clay. Clay was consisted of illite, kaolinite and chlorite evenly. Soil material J was composed of 68.92% silt and 11.67% clay. Clay consisted of smectite only. 4. Coliphage was absorbed to soil material J more than soil material SW, and $T_1$ coliphage was absorbed to soil material more than $T_5$ coliphage was. 5. The phage adsorption efficiency to soil material was enhanced at lower pH : the phage adsorption efficiency at pH 4 was 27 time higher than at pH 7. 6. Divalent $(Ca^{2+})\;and\;trivalention\;(Al^{3+})$ enhanced the phage adsorption efficiency to soil material from 4 to 39 and from 17 to 91 times higher than monovalent $ion(Na^+)$, respectively. 7. The concentration of organic compound was inversely related to the phage adsorption efficiency to soil. 8. Adsorption of phage onto soil material, and elution efficiency of elutants was in the order of D.D.W>tap water>river water>seawater. 9. The higher the concentration of organic compound was, the more were adsorbed phages to soil eluted. 10. Coliphages survived longer in sterile soil suspension than in nonsterile soil material suspension.

• BMB Reports
• /
• v.39 no.1
• /
• pp.55-60
• /
• 2006

We describe a phage display strategy, based on the differential resistance of proteins to denaturant-induced unfolding, that can be used to select protein variants with improved conformational stability. To test the efficiency of this strategy, wild-type and two stable variants of ${\alpha}_1$-antitrypsin (${\alpha}_1AT$) were fused to the gene III protein of M13 phage. These phages were incubated in unfolding solution containing denaturant (urea or guanidinium chloride), and then subjected to an unfavorable refolding procedure (dialysis at $37^{\circ}C$). Once the ${\alpha}_1AT$ moiety of the fusion protein had unfolded in the unfolding solution, in which the denaturant concentration was higher than the unfolding transition midpoint ($C_m$) of the ${\alpha}_1AT$ variant, around 20% of the phage retained binding affinity to anti-${\alpha}_1AT$ antibody due to a low refolding efficiency. Moreover, this affinity reduced to less than 5% when 10 mg/mL skimmed milk (a misfolding-promoting additive) was included during the unfolding/refolding procedure. In contrast, most binding affinity (>95%) remained if the ${\alpha}_1AT$ variant was stable enough to resist unfolding. Because this selection procedure does not affect the infectivity of M13, the method is expected to be generally applicable to the high-throughput screening of stable protein variants, when activity-based screening is not possible.

• BMB Reports
• /
• v.33 no.3
• /
• pp.242-248
• /
• 2000

Phage display of proteins is a powerful tool for protein engineering since a vast library of sequences can be rapidly screened for a specific property. In this study, we develop da new phage display vector that was derived from a pET-25b(+) vector. The pET-25b(+) was modified in order that the expressed protein would have a T7-tag at the amino terminus and GpS (a major coat protein of M13 phage) at the carboxyl terminus. Another vector without the gp8 gene was also constructed. The newly developed phagemid vectors have several advantageous features. First, it is easy to examine whether or not the target proteins are functional and faithfully transported into the periplasmic space. This feature is due to the fact that recombinant proteins are produced abundantly in the pET system. Second, the T7-tag makes it possible to detect any target proteins that are displayed on the surface of filamentous bacteriophage. To verify the utility of the vector, the clones containing the glutathione S-transferase (GST) gene as a target were examined. The result showed that the GST produced from the recombinant vector was successfully transported into the periplasmic space and had the anticipated enzyme activity. Western blot analysis using a T7-tag antibody also showed the presence of the target protein displayed on the surface of the phage. The phages prepared from the recombinant clones were able to bind to glutathione-Sepharose and then eluted with glutathione. These results showed that the new vectors developed in this study are useful for the phage display of proteins.

• Preventive Nutrition and Food Science
• /
• v.5 no.4
• /
• pp.219-224
• /
• 2000

Dieary effects of sea tangle on immune functions were investigated in diabetic mice. Four groups of ICR mice weighing 33.36$\pm$1.01 g were fed either an AIN-76 diet only (control), or with additional sea tangle powder, sea tangle water extract, and alginate at the level of 13.6%, 4%, and 1%, respectively by weight. Cellulose was omitted in sea tangle powder and alginate diets. After 10 days of feeding respective experimental diets, all mice were made diabetic by five consecutive intramuscular injections of streptozotocin (40mg/kg body weight per day) and fed the diets for four more weeks. Plasma IgG concentrations but not those of IgM were significantly higher in mice fed sea tangle powder, extract or alginate than those on the control diet. Plasma TNF$\alpha$ levels were, however, lower in those fed sea tangle power or water extract than control and alginate fed groups. TNF$\alpha$ releases from macro phages isolated from four groups and cultured with 5 $\mu\textrm{g}$/mL LPS for 24 hors showed a similar tendency to the results of plasma concentrations in the respective groups, but IL-1$\beta$ releases were not different among four groups. Lymphocyte proliferation in response to LPS (10$\mu\textrm{g}$/mL) measured using splenocytes cultured for 3 days was highest in the alginate fed group (594$\pm$38%) and those of sea tangle powder (536$\pm$47%) and extract (547$\pm$34%) fed groups tended to be higher than the control (523$\pm$30%). It is concluded that sea tangle contains immunomodulatory components besides alginate that could enhance humoral immunity of itself. The immunomodulatory effects of sea tangle constituents is regarded as beneficial for diabetic subjects.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.22 no.5
• /
• pp.1270-1275
• /
• 2008

Effects of polysaccharide fraction from Euonymus alatus Sieb(EPF) on the immune response of T-, B-lymphocytes and macrophages were examined in vitro and in vivo system. EPF (500 mg/kg) were administered p.o. twice a day for 5 days to C57BL/6 mice, and then the cells were separated from mice. EPF decreased the viability of thymocytes, but increased the viability of splenocytes in vitro and in vivo system. Also, the administration of EPF enhanced the population of helper T cell and cytotoxic T cell in thymocytes and did not affect the population of splenocytes. Furthermore, EPF enhanced the phagocytic activity and the production of nitric oxide in peritoneal macro phages in vivo system. These results suggest that EPF regulates an immune response via the enhancement of mature T lymphocytes and B lymphocytes viability and phagocytic activity of macrophages.